Determining the location estimate of a wireless device can be based on measured signal strength, such as Received Signal Strength Indication (RSSI), Access Point (AP) location, a path loss estimate, and transmit power of the wireless device. In many scenarios, however, the transit power of the wireless device is unavailable. For example, WiFi clients may change their transmit power based on heuristics, or there may be variability and uncertainty in the transmitter of the wireless device. Incorrect estimation of transmit power can lead to location estimation errors.